Saturday, May 31, 2014

StirPlate Transmission pt.3

Not much left to go now and Ill have the mechanism for stirring through the entire range of rpm's I could possibly want. I haven't given the enclosure much thought since the last blog entry where I showed the pics of the hacking and butchering I've done on the crappy little enclosure I got from Radio Shack, excepts to think that I want something a little sturdier. Ive spent so much time with this gear box, or transmission, or whatever you choose to call it, that I can hardly bear to put it in that crappy, flimsy enclosure. I also wish I still had those heating elements I got from Science Surplus last year, or the year before. They would be perfect for adding heating capability to a stirplate. I'm not even sure if I can find that kind anymore, and I certainly cant get 2 for $4 anymore(can't remember exactly what I paid, but it was obscene). Oh well, no heat on this one, its a first build. I wanna do another with metal gears that wont melt and, of course, heating elements!  All inside an enclosure made from sheet aluminum bent on a tiny brake, like this one. There is a shared shop around here you can pay by the hour or get unlimited access to a fully equipped machine shop for $1200/year that has every damn thing. I haven't paid for time there but did go talk to them and fill some stuff out, look around etc. Id like to have some sort of a paying gig before I put any money down, even though you aren't allowed to run a business from the shop, it would be nice to be making a few dollars, just a few, that would be awesome.

Here are some pics of the transmission/gearbox/frankenstein after remaking the pivoting bar and rethinking the design a bit. The big aluminum one will carry the magnet(s). Its bearing, one from a r/w head from a hard drive, will turn about the same axis as the pivot bar pivots, so it never moves with gear changes and the belt maintains a constant tension. It has a groove matching the other pulley(borrowed indefinitely from a cd-rom drive) machined around it. I put a different, bigger, gear on the servo because leaving that idler gear then adding the pulley, and therefore length, I needed to get further out to keep my linkage at a kosher angle.

You can see the end of the bolt at the bottom of the pivot bar is not all the way screwed down. Itll all work out when the big aluminum pulley is mounted.
Here's a side view for good measure. You can actually see in this pic that the linkage is not yet attached to the copper gear. I still had to work out the height, which is now to the top of the pulley, not the idler, like it was. 

Wow, look at that clearance lol. You can scarcely get a piece of paper between the black pulley and the aluminum one. Im considering taking a bit more off the od , but I really don't want to, since Id have to remachine the belt groove too on top of making a special arbor just to turn that little bit off. Screw all that, besides, its not rubbing or anything, it actually has about .04", plenty. The copper gear and black pulley are not on the same plane, so they miss each other by a lot.

Look at how fat I have made this dog. Thats not why I took the pic, though. If youll notice under her 'arm', you'll notice a white streak or something. That's a steak bone. She never lays like that either. She is actually laying on it to 'protect it' lmao. She's a trip lol. Im gonna stop feeding her off my plate like I do, cause damn lololol

Thursday, May 29, 2014

OSGP pt.2

Here's a couple pics showing what I have to work with. I'm pretty curious to see if that little burner is even gonna give me 220F. If not, there are things we can do that could squeeze a few more degrees out. Some, like insulating the body with a welding blanket, is something I want to do anyway. Besides that, Im sure there are a number of ways to adjust how hot it burns. Surely there is some way for me to tweak the fuel/air mix. If not I think I can make that happen anyway.

Looking at the valve for this burner, and how it connects to the burner, it's different than the burners in the gas grill side. The valve assembly, how it connects to the burner, the burner where the valve goes in--all of it is different than the other grill's burners. So, I don't feel 100% comfortable taking too wild of liberties with the way the valve relates to the burner and tube. This means that rather than putting the burner right in the middle of the grill, where Id rather it be, I have to put it on the end and that fat ass valve assembly dictates which end.

I don't know if I will be able to get away with making me a place to mount the valve assy. As I said, I'm afraid to deviate too much from the way it was when it was where it was designed to be. But I don't like the idea of attaching the valve assy to the grill body. I need to nail those dimensions down by dry fitting shit until I have a place to put it besides straight on the grill body.

I need a longer hose than the one that is already attached to the valve assy. Besides that, I just need to get a drill so I can open up a hole or two for the burner to go. Then, I plan to fix some kind of basket over the burner for wood chips. I want to mount a thermistor in there before I start using the grill, because I know that already having a sensor attached and dry wired in will help keep me motivated on the true mission of the OSGP, to make a bad ass grill.

It doesn't quite reach to the center, but it'll be close enough.

Will she make smoke and hold 225? Id actually like it to go to and hold 300 as well, we'll see.
The valve assembly with the knob removed. You aint squeezin' that in between nuthin'

OSGP pt.1

What is The OSGP?
OSGP stands for, the Open Source Grill Project. The end goal is to have a programmable grill, preferably charcoal. The grill should be sealed as well as possible so that any air reaching the coals is air the microcontroller pushes on the coals via a small fan. By using a well tuned PID controller and a small fan you can achieve a surprising level of control over the temperature. Of course, the well tuned part, is the most difficult part of the whole endeavor in my opinion. Well, I dont really have to concern myself with that anymore since the HOA told me that if I use a charcoal grill on the property again I would be fined $250. As painful as it was bound to be, I resolved to go a year with no bbq since I'm not a fan of gas grills. It was my opinion that the only thing gas grills had going for them is, how quickly you can be cooking when the urge hits. Just turn on the gas, hit the igniter button, and you're cookin'!

My wife is the one responsible for the purchase of the gas grill. Her prejudice doesn't run as deep as mine regarding how 'real' bbq is made. I am talking about real bbq, too, not hamburgers and hotdogs or the like, but pulled pork, ribs of all kinds, briskets--things you cook at low temperature with smoke. Once I was told to find a gas grill that would be in compliance with the ridiculous bylaws of our HOA, I set out to find one, with very little hope of being satisfied. A thousand dollar budget would have made for an easier job, but hahaha, no. Much to my surprise I found a grill that I really truly love. If you knew me you'd be amazed at that statement, for I am outspoken about the need for charcoal when it comes to smoking meat, there is really no substitute. I have come to realize however, or strongly believe, that a gas grill can be modified in to a lean mean smoke ringing machine. The grill I settled on is the Duo by Char-griller. It has a charcoal grill and a gas grill side by side. It also has a side burner, that I cant imagine a single use for. Perfect.

The Plan  
At first I planned to sneak in some charcoal cooking just for long smokes, since I think I could get away with it pretty easy. Then, I got a much better idea--I thought, why not take the burner from that side burner that Ill never use, and install it in the charcoal grill? I will probably have to make a few parts to get it to work, that's a plus, Ill also need to modify the grill body to accommodate the hose, the burner, the temperature knob etc. I want to mount a stainless steel bowl to the burner for holding wood chips. These grills are pretty big, each one could pretty easily handle 3, maybe even 4, racks of baby backs. That small burner with a stainless steel bowl full of wood chips would most likely not be able to get the grill above 200F-250F. Since I smoke almost everything at ~220F, this could be perfect(after pondering all this, I now feel I need to be able to squeeze, at minimum, 300F from this grill to consider it a success). I also want to see if I could use an arduino to do what I had originally planned for my Kettle, except rather than stoking coals with a fan, control a solenoid on the gas line. I suspect this may actually afford even finer temperature control than air/coals. As for that shelf with the nice lid that used to cover a burner,  I will be cutting that metal out and mounting a box there, perhaps aluminum with some connection to the larger gas grill that would allow heat to move in to the box. That would make a really nice warming box and also a nice place to store utensils when not being used.

Here's the burner removed from the side
 shelf and laying in the charcoal grill.
 You tell by how small it is that it would
 never get things hotter than 250F,
 maybe not even that hot. Perfect for smoking.
The burner-less shelf. This will be cut
out to accommodate an aluminum box
for storing utensils and perhaps a warming

Wow, this is all of the sudden a potentially fun project. Last night I assembled the grill according to instructions, ie no mods yet, I will cook a couple steaks tonight to celebrate human dominion over cows. The modifications will commence immediately after. My imagination is going wild at this point, thinking about all the different ways in which an arduino and a few other components can and will make this into a bad ass grill, way cooler than anything you will ever see for sale on a large scale, at least in your typical place that sells grills(save actual grill stores that only sell awesome grills). I don't doubt there are some bad ass grills out there that do all kinds of awesome stuff, but I don't know where you'd find them and I couldn't afford one anyway. Btw, in case you're wondering, the Duo cost $299. Not bad at all, especially considering its 18 months no interest.

That's the basics of what's going on with the new, and potentially improved, OSGP. As things actually begin to happen, I will of course post about it here. I should also mention to those who may not know, that an arduino controlled charcoal grill is not my idea alone. Though, I did think about doing it way before I heard about the BBQ Guru or The Stoker, similar gadgets that enjoyed some popularity because of the show BBQ PitMasters on discovery, where they are used by pretty much everybody cooking on small to medium sized grills. There have also been diy versions of these simple devices pop up on a blog or two. Nothing about the device itself is unique, its old news. My vision for what it's capable of, however, I think is a bit broader than what I've read or heard from other people. I envision cooking profiles that can be programmed, ie hold 225F for 7 hours, then jump up to 300F for an hour may be a rib profile. I also imagine people trading these profiles. At some point after its basic evolution is complete you could conceivably have a set up so simple that all you would need to do is load the program and throw your meat in there and wait. Especially with a gas grill with electronic ignition etc. All you'd need to do, besides throw some animal muscle on there to cook, is turn the gas on, unless you attached a servo or two for handling knobs, dont think I havent thought about that :^)

Ill leave you with a few more pics of the grill in various stages of assembly, and will post again when the modifications start. This one could get interesting, besides its been a long time coming. I've been wanting to marry arduino and grilling for quite a while. Let's do it.

I wonder if I can get an extra knob and an lcd screen on that panel on the right?

Its a big bastard. I love it. I'm shocked that I do, but I do.

The big empty charcoal side looks like infinite possibilities to me

Saturday, May 24, 2014

StirPlate Transmission

It works, but I want to do it a different way. I will finish what Im doing here, but I have the itch to build something bigger now that changes gears. Anyway, peep the video and of course there are millions of pics on my web album, though I cant figure out how the hell to link it.

The arm that moves the black idler gear around will have to be remade again a bit longer to hold another gear on the very end which will be towards transferring that awesome hi/lo gear selected motion to a common rotor equipped with magnets. The problem is I keep changing my mind about how I want to do the whole thing. There are a lot of ways to do this shit. Some ways go well until the end, some dont ever really go well and some are just fantasy. I do want to redo this whole thing with metal gears and a heating element, though. Its gonna happen dammit.

Friday, May 23, 2014

Shoring Block

I hit another stopping point with my so-called shoring block. Putting together rigid setups, especially using the milling attachment, is not easy to do. Its my opinion that much of the problem is the crazy overhang of the milling attachment off the top of the cross slide. The shoring block, as Ive decided to name it, just slides under and, hopefully, provides some support. You can see the finishes on the block are absolute shit. Im really hoping that I can get a bit more rigidity from these setups and start milling some better looking pieces.
You can see there is absolutely nothing under the milling attachment.

Here you can see how the shoring block just fits underneath the milling attachment and is milled to fit on the way prism the notches on the cross slide.

Here she is. Not quite done, but does atleast lay under there for some support.

The Great Stir Plate Transmission

The stir plate transmission is going pretty well. I should have some gear changing action going on soon. Right now its deciding which way to go with it thats holding me up. I love taking a box of parts from all sorts of shit and seeing how I can make it fit together in to new things. All these gears and racks a bearings all fit together in so many ways. In this post Ill lay out my possibilities.
The black gear is the one I hope will jump from gear od to gear od and give me high/low.

The servo is nearby, great.

Another part Id like to see used. Its a pivoting arm. Notice in the next pic the beautiful bearing fit.

The bearing from a hdd head looks as if its made for my pivot arm I found.

The latest idea is a rack and pinion off the servo. 

Maybe come in at an angle parallel to the center lines of the gears?

This is gonna be so bad ass.

Saturday, May 17, 2014

Much Needed Lathe Mods - A Better Z Axis

Trying to use the Z axis hand crank for anything besides straight, light cut OD turning with no shoulders to deal with or Z axis dimensions that are even kinda close, like +-.03", will end in failure if you use that shitty rack and pinion setup that these mini lathes ship with. In a nutshell, any attempt to machine something along the Z axis quickly turns to shit. Turning tools grab and pull the carriage into the work, or when using the milling attachment, end mills do the same thing--grab and pull and dig in and fuck up whatever it is youre doing. Youre lucky if you dont break the end mill. Plunging an end mill slowly with high rpm, or any combination of  still doesnt help in the least. Up until now Ive had to avoid parts that had medium to high tolerance work along Z axis; counterbores with +-.005" on the depth or  something similar. Plus or minus .005" is not what I would call high precision, and I couldnt even do this the way things were. The good news is, there's an easy fix that works great. Basically we are going to steal an idea from the cnc conversion and also from our common sense that already knows good and damn well that a lead screw of any kind is preferable to a rack and pinion.

Im a bit slow sometimes and Im ashamed to say that this idea wasnt immediate, the way I feel it should have been, looking at it now. The rack and pinion has a good .02-.04 drift in whatever direction pressure is being applied and since the rack and pinion design was designed to transfer loads in a particular way that offers absolutely no resistance if pushed or pulled in either direction along its axis, even facing can be a white knuckle operation when youre taking the last few thou off and your finish size is plus or minus .0005". I have several parts that have tight OAL(over all length) dimensions in the drawings for my 4 cylinder stirling. The only way I was even able to pull it off is because I could get the tool well away from taking any cut, then using an indicator to move the carriage a few thou, then clamp the carriage down in position and slowly go over the face a few times until it doesnt even take dust. Between the shitty rigidity of the compound to begin with and then only a rack and pinion setup to hold the axis still, results were truly disappointing. Thats when it dawned on me.

I could engage the half nut to lock down the carriage when facing. That would better than trying to clamp the carriage down. I also considered a carriage locking method to be a top priority mod since I was basically unable to cut a truly flat face without considerable pains in my ass. What I discovered once I started experimenting with using the half nut to lock the Z position of the carriage is that turning the lead screw by hand with the half nut engaged was pretty easy and that moving it this way had almost zero backlash, with an indicator I could easily dial off a couple thou or even tenths, if I trusted my indicator like that, and I didnt really need to change anything else and Id have not just a decent Z axis feed, but a damn good one. The plan was to machine a handle with knurled edges and possibly a smaller handle for faster spinning, but the handle was absolutely needed and I already had a piece of material that not only was the perfect size, the machine work was almost done already. I still havent finished, or even started on the handle yet since all this other shit seriously side tracked me, but it was worth the distraction.
My earlier method of using a clamp to
attempt to lock the carriage in position
for milling or facing.

The next thing I did was remove all the change gears, and set the feed direction lever to neutral position. Now I have no gears on the back of the machine being powered. This makes it much safer for me to be groping around back there blind, spindle running a couple thousand rpm. The thought of accidentally sticking my finger in those meshing gears pretty much scared me to the point that I didnt want to leave a single gear attached except the one I intended to use as my temporary handle.

Thats pretty much the whole story of how the Z axis found itself being scrutinized by me and subsequently modified to work more like a white man's machine. Ill just show the porn and that should clear up any remaining confusion.

Here all the change gears have been removed and the largest one I have has been put on the lead screw to use as a temporary handle. Larger diameter is easier to turn by hand and this is the biggest gear I have. The cluster of  two white gears directly underneath the spindle gear are not engaged, neither is the gear under that. That big ass gear did make for pretty easy turning of the lead screw with the half nut engaged, but I pretty quickly realized I could make a way better temporary axis jog handle.

This piece of material is damn exactly what I need already. Its too perfect to not do it. I havent even started on finishing this part. It will be knurled on the OD and have a spin handle the way my temporary one does (you havent seen that yet). Ill also need to mill a keyway in it. A broach would be badass.

Here is the temporary in all its glory with spin handle installed. I dont know what else to call the bolt with a piece of aluminum tubing over it besides a speed handle. Because it does make it possible to spin it up pretty fast and get Z moved around quickly. I should also note that Im even getting less chatter using the new method of Z axis feeding/cutting.


Here Im finally setup to make a permanent handle. The indicator is setup somewhere that is not affected by Feeding X and using my temporary handle I have very fine control over Z. Soon as I get the handle finished Ill post it in all its glory.                                                                                

This was definitely something I should have done a long time ago, but it never occurred to me. I can do a slower feedrate by hand and get a better finish. It pushes though heavy cuts way easier, almost too easy and you bog it down. And the virtual absence of backlash is also fucking killer. I need to make a brass half nut and I need to change the spindle bearings. It seems so stupid to me that a mini lathe manufacturer would skimp $20 on construction of a machine for such a vital role. But they all do it except maybe the high end smaller stuff. They all put fucking skateboard bearings on the spindle rather than real spindle bearings, tapered pins that can take any load you can hand the spindle. At first this shit didnt chatter real bad, but as those suck ass bearings start to wear in, I get constant chatter it seems like.  Im still pretty spoiled on industrial grade shit. I have no experience playing with a hobby lathe. I do have perhaps higher expectations when it comes to depth of cut and rigidity.

I think its obvious what has to come next, the dro from digital calipers. I already butchered the calipers, just need to mount it. 6 inches beats 1 inch on a shitty indicator. Ive never had such shitty tools. Its really all junk. Even the mics, which ill usually trust cheap mics, are dodgy as fuck. Either way, the caliper readout beats a shitty indicator.


I took that hand wheel off the carriage so Ill quit grabbing for it. Ive had a chance to cut on the aluminum piece a little and and extremely pleased at how much better actually using the machine is. I need to fuck with mounting my steppers too. Thats coming soon I get the feel. At least the Z axis. Im so happen with this little shit, Id prolly shit if I had some faintsee pire feed. But, if I do one I know the others will get done too. I would prolly know all kinds of cool shit to do if I really dug around online. I dont know why I dont do that type shit anymore, voraciously seek shit out online, I mean.

Interpolated by hand for the most part. It was polished with some 220 emery, but other than that it was all interpolated thanks to using the Z axis leadscrew for handfeed. Chatter also definitely reduced. 

Much Needed Lathe Mods - A Little More X

There are a couple of things that have been a pretty consistent source of aggravation when trying to work with my mini lathe, one is how it seems like Im always looking for a sweet spot. Depending on the part, I have to decide where I want to lock down the compound and the tool post, so I have enough travel to do an entire 3" face but the angle of my tool post or compound aren't so extreme I can still do other work without having to tweak my setup in some way. Basically when you're at the limits of your travel and working envelope it gets harder and harder to use both axes completely without having to move something, for instance when going from facing to turning or to turning from boring and those sizes are way out near your limits, switching tools can be a lot more of a job than simply throwing the relevant tool holder on your handy quickchange post, and making chips, like youre accustomed to.. So, its a big deal that I gained over an inch on X. I have some 4" material I haven't even considered for much, because I was pretty much maxed out at 3".

I stole the extra travel by turning the compound back almost to 180 degrees, pointing right at me. Its about 25 degrees shy of making 180. Moving this around I can squeeze a out little more if Im ever pushing limits again, which will no doubt happen.  Honestly though, I think the bed is going to be a size barrier before X travel. Im not 100% sure, but Im pretty damned sure that I have more X travel now, than I have actually space to accommodate a piece of material that big.

Of course it wouldn't even be worth mentioning if I didn't have to modify something to make it work. The retaining block that holds the feed screw in the compound was hitting parts of the cross slide, so clearance had to be created by grinding the bottom of the retaining block. The pics are pretty self explanitory. Speaking of pics, you'll notice that the handle and the dial are gone from my compound slide as well. Im not a big fan of the compound slide and dont use it much anyway. The machine is just too small to try to squeeze it in. Threading is the only time when its even remotely useful imo, and since in that case it would be in a more 'standard' position of 29 degrees(damn I gotta see how to do a degree symbol) I can just put them on when needed. I need the travel more than I need to thread.

You can see the retaining block being an asshole and ruining my inspired, clever, simple idea--to flip the compound around and claim my free prize, a truly larger work envelope. The block doesnt do anything besides attach that feed screw to the top half of the ways so it can be moved against the tapped hole in the bottom half, the swivel base part. Grinding some off the bottom wont affect anything in how it operates, when I do want to use the dial and handle it will still work fine. To keep the compound as immobile along its own axis as possible, I have the gibb screws pretty tight. This should be fine.

After the grinding and a bit of filing, it clears. I know it looks a bit catiwampus, ie the angle of the new flat is not parallel with the top half of the cross slide. It cant be easily seen, since its at the back of the machine, and it has no impact whatsoever on how it functions. I could always mill it a bit deeper, make it parallel as hell, but I have no fucks to spare at the moment on such a pointless thing.

Here you can see the total amount of extra X clearance I picked up. And yes, I can easily make it to center and beyond without having to change the angle of the compound or the tool post. Also, switching out the type of tool, like boring bar to turning tool, or especially from turning to parting off or threading, now I can just throw the needed tool on the tool post and start making chips. You can see in this pic the approximately 25 degree angle of the compound. At first I had planned to keep the compound at 180 once I had clearance on the retaining block, but the rest of the compound slide etc were hitting the part when the tool was only about .600" in on Z. Where it is now, around 25 degrees, gives me a mile all over, everything fits with plenty of room to spare. Usually when Im out in the 3" neighborhood like this, tool changes can become rather involved and shitty. Ive been through some shit with that damn part off blade and 3" material lol. It fucks your whole roll up when just a tool change takes more than a few seconds to a minute, especially if you're high too. It makes trying to maintain any momentum a joke. I think that now, I at least have a chance stay focused on the actual machine work when working with 3"+ rather than jugling shit around.

I was actually pushed in to doing this tonight by starting on the other mod, to be discussed next, and running into travel issues right away. That's actually the offending part in the chuck in that last pic. That piece will become a handle. It'll all make sense after the next post.


Tuesday, May 13, 2014


The stirplate is underway and actually works already. Right now its running off my 2560 with my motor shield. I never use them, so I figured why not. I also wanted to get good torque at low rpms. Looking at some of the diy stirplates on youtube where people just used a potentiometer, their lowest setting is still fast as hell. A good stirplate will have a complete range of rpms available. Im also pretty keen on having something programmable. It may seem to us that something is stirring pretty completely, but in fact it could take more than 24 hours to stir completely. I hope to change this but pulsing and otherwise mixing up how mine stirs. Im not 100% pleased with the low rpm limit. In my sketch the lowest power I can apply and get movement is 50. Im not sure how many rpms that works out to be, but its more than I want. See it in the video, that is the lowest setting(I know that racket is god awful, its just a bolt clanking around in there, I plan to get a legit stirbar today. The other video shows testing how well it changes directions. THe motor mount, the black box that holds the motor, was made from pieces of a cdrom tray that I cut up and epoxied together. Im pretty pleased with how well it holds everything. I will use this approach again. I havent started mounting it all in the enclosure yet since Im not satisfied with it. Ill leave it at that for now. Here's the pr0n--